A thermodynamically stable La_2NiO_(4+δ)/Gd_(0.1)Ce_(0.9)O_(1.95) bilayer oxygen transport membrane in membrane-assisted water splitting for hydrogen production

摘要

A bilayer configuration of mixed ion-electron conducting La_2NiO_(4+δ) and oxygen-ion conducting Gd_(0.1)Ce_(0.9)O_(1.95) (LNO/GDC10) was proposed for hydrogen production by water-splitting and its properties were measured as a function of temperature, reducing gas CO content and water vapor pressure during the hydrogen production by water-splitting. The hydrogen production flux increased with increasing water vapor pressure and oxygen chemical potential to a maximum of 0.12 cm3 (STP)/min-cm~2 with 23.25% CO/76.75% CO_2 (40 sccm)/balance He (60 sccm) gas mixture on the oxygen-permeate side and wet N_2 (pH_2O=0.49 atm) on the oxidizing side at 900 °C. The stability of the bilayer membrane was tested in a very low oxygen partial pressure (pO_2) on the oxygen-permeate side. The presence of GDC10 on the oxygen-permeate side of the bilayer prevented the direct exposure of LNO to very low pO_2 and thus protected it from decomposition, even at pO_2 ≈ 10~(-15) atm.